filler turtle

--dofile("api.lua");

local chesttname = "minecraft:chest";

local pos = {};

local function RefuelIfNessesary()

    local level = turtle.getFuelLevel();
    if level=="unlimited" then
        return true;
    elseif level < 1 then
        turtle.select(1);
        if not turtle.refuel() then
            return false, "unable to refuel, slot 1 not fuel or empty";
        end
    else
        return true;
    end
end

local function IsFacingBaseChest()

    local item = turtle.inspect();
    return type(item)=="table" and item.name==chesttname;
end

--Must be facing the chest for this to work
local function GetFuelFromChest()

    turtle.select(1);

    if turtle.getItemCount() >= 64 then
        return true;
    elseif not IsFacingBaseChest() then
        return false, "Not facing base chest";
    elseif not turtle.suck(64) then
        return false, "base chest is empty";
    else
        return true;
    end
end

local function Calibrate()

    local foundchest = false;

    for n=1,4 do

        if IsFacingBaseChest() then
            foundchest = true;
            break;
        end

        turtle.turnRight();
    end

    if not foundchest then
        return false,"base chest not found, please place me next to the base chest";
    end

    --We're facing our base chest here

    local ok,msg = GetFuelFromChest();
    if not ok then
        return false,msg;
    elseif RefuelIfNessesary() then
        GetFuelFromChest(); -- get more
    end

    turtle.turnRight();

    local steps = 0;
    local blockf = turtle.inspect();
    local blockd = turtle.inspectDown();

    while not blockf and blockd do
        if turtle.forward() then
            steps = steps + 1;
            blockf = turtle.inspect();
            blockd = turtle.inspectDown();
        else
            return false,"Cannot move forwards (no fuel?)";
        end
    end

    pos.base = {x=steps,y=0,z=0};

    print("base is at X offset: "..tostring(steps));

    --we're now at _our_ 0,0,0 facing forwards
    --now turn and travel down the y axis

    turtle.turnRight();

    steps = 0;
    blockf = turtle.inspect();
    blockd = turtle.inspectDown();

    while not blockf and blockd do
        if turtle.forward() then
            steps = steps + 1;
            blockf = turtle.inspect();
            blockd = turtle.inspectDown();
        else
            return false,"Cannot move forwards (no fuel?)";
        end
    end

    local yMax = steps;
    print("Y Max: "..tostring(yMax));
    --now walk back
    turtle.turnRight();
    turtle.turnRight();

    for n=1,yMax do
        if not turtle.forward() then
            return false,"Cannot move forwards (no fuel?)";
        end
    end

    --Now we're at our 0,0,0 (in a courner)
    turtle.turnLeft();

    steps = 0;
    blockf = turtle.inspect();
    blockd = turtle.inspectDown();

    while not blockf and blockd do
        if turtle.forward() then
            steps = steps + 1;
            blockf = turtle.inspect();
            blockd = turtle.inspectDown();
        else
            return false,"Cannot move forwards (no fuel?)";
        end
    end

    --Now we've travled down x
    local xMax = steps;
    pos.grid = {x=xMax,y=yMax};

    print("X Max: "..tostring(xMax));

    --now walk back
    turtle.turnRight();
    turtle.turnRight();

    for n=1,yMax do
        if not turtle.forward() then
            return false,"Cannot move forwards (no fuel?)";
        end
    end

    print("I'm now home");

    pos.pos = {x=0,y=0,z=0,face="right"};

    return true;
end

local function Up()

end

local function Down()

end

local function Right()

end

local function Left()

end

local ok,msg=Calibrate();

print(ok,msg);